has anyone else experience this.....

I normally get my tubes from andy of vintage tube, put had been calling around talking with some of the other pundits selling tubes and got burned so to speak...

TLS, thanks for the good articles, and the good points you provided in your post. As you and Bill_K indicated, the term NOS is unfortunately used too loosely too often. With the problem being further compounded by the existence of fakes, as Elizabeth pointed out.

As a potential purchaser, everything else being equal I would feel much more comfortable purchasing from a seller describing a tube as "used but tests as new" than from someone who simply describes it as NOS.

Also, I must say that personally I wouldn't want to be without a good tube tester (I have a vintage Hickok 800A), in part to minimize the possibility of component damage such as the OP has unfortunately experienced.

Best regards,
-- Al

Fake Mullards? What's next, fake Badboys? Fake Tung Sol Round Plates?

Actually most dealers worth their salt stipulate whether they are selling new NOS tubes, used NOS tubes that test like new or whatever. Almost every seller provides test results and point out if the results are "marginal."

Al, you're welcome. Always glad to provide helpful information.

The Brent Jesse site also has a lot of other good info about vintage tubes, as well as some instructional videos identifying certain vintage tubes. The following websites have many pictures of vintage tubes that may also help with that vintage tube identification.

tubeworld

tubemongerlib

I acquired the Brimar 12AT7's many years ago that I previously mentioned, and for quite some time was unsure about them being authentic, as they were different from all other pictures of Brimars I found. After finding a picture on the Tube World site, I then felt they were a real vintage tube. This was also confirmed when I allowed a few local friends to try them, and they did not want to return, but asked to purchase them.

BTW, I also have tube testers, a B&K 600 for quick simple testing, and a Hickok 752 for more serious testing. Although the Hickok seems to work reasonably well, I am curious about your thoughts on calibration of this tester.

Tony